SWI/SNF was the first ATP-dependent chromatin remodeling complex to be identified and since then a myriad of different ATP-remodeling complexes have been identified with varying functional roles in the cell. All eukaryotes possess SWI/SNF and in humans SWI/SNF has been shown to be involved in many aspects of cell development, differentiation and cell cycle control. Aberrant SWI/SNF has been shown to be linked to cancer and its onset. Although some aspects of the interactions of SWI/SNF with nucleosomes and the manner in which it remodels nucleosomes is known there is still much that is not well understood. We propose to extend earlier studies by further examination of the interactions of SWI/SNF with nucleosomes, the mechanism of SWI/SNF remodeling, and the effects of histone modifications and auxiliary proteins on SWI/SNF remodeling.